High penetration of Distributed Energy Resources (DERs), especially at low-voltage networks may introduce power quality problems such as voltage sags and swells, and may exacerbate voltage harmonics on a grid. Conventionally, these negative effects of DERs were mitigated by centralized bulk devices at the medium-voltage level, such as at a plant or a substation. For example, static compensators (STATCOMs) and static VAR compensators (SVCs) may be provided at a central level to regulate line voltage through reactive power control. These semiconductor-based devices may actively regulate the reactive current injected into the grid and may provide faster and finer regulation than mechanically-switched voltage regulators such as Line Tap Changers (LTCs). These systems, however, may fall short of resolving problems arising at the leaf end of a distribution network due to massive DER penetration, especially in residential and commercial markets. For example, due to their centralized existence at the medium-voltage level, the visibility of such systems to problems locally occurring at low voltages may be limited. Also, as low-voltage distribution networks have smaller ratios of reactance to resistance (X/R ratios), the effectiveness of reactive current injection may be muted.
SVCs on a low-voltage network (μ-SVCs) may overcome some of the problems of centralized bulk devices at the medium-voltage level, as the distributed deployment of μ-SVCs may mitigate negative effects of DERs at the source, thus blocking their propagation to the medium-voltage network. μ-SVCs, however, may be bulky, may offer limited power control, and may fail to adequately compensate for grid voltage harmonics.